JP2013064200A - Method and apparatus for vaporization of deposition material in substrate processing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deposition system for performing chemical vapor deposition comprising a deposition chamber and a vaporizer coupled to the chamber.SOLUTION: The vaporizer has a relatively short mixing passageway to mix a carrier gas with a liquid precursor. The mixing passageway produces a fine aerosol-like dispersion of liquid precursor, wherein the dispersion is vaporized by a hot plate 280.

Description

  The present invention relates to the field of integrated circuit manufacturing. In particular, the present invention relates to an improved method and apparatus for depositing material in a deposition processing system.

  Currently, aluminum is widely used in integrated circuits for interconnections such as plugs and vias. However, as device density increases, operating frequencies increase, and die size increases, it is desirable to use metals in the interconnect structure that have a lower resistivity than aluminum. Techniques for depositing copper, including electroplating, chemical vapor deposition (“CVD”), and physical vapor deposition (“PVD”) are well established. A CVD process is a desirable process because it is often possible to obtain a more compliant deposition layer. For example, chemical vapor deposition of copper can be achieved by using a liquid copper compound precursor known as Cupraselect® having the chemical formula Cu (hfac) L. Cupraselect is a registered trademark of Schumacher, Carlsbad, California. Cupraselect consists of a deposition controlling compound such as (hfac) and copper (Cu) bonded to a heat stabilizing compound (L). (Hfac) represents hexafluoroacetylacetonate, and (L) represents a ligand-based compound such as trimethylvinylsilane (“TMVS”).

During copper CVD using Cu (hfac) L, this precursor vaporizes (evaporates) and flows into the deposition chamber in which the wafer is located. Within the chamber, the precursor is leached with thermal energy at the surface of the wafer. It is considered that the following reaction occurs at a desired temperature.
2Cu (hfac) L Cu + Cu (hfac) ₂ + 2L (Formula 1)
The resulting copper (Cu) is deposited on the top surface of the wafer. Reaction byproducts (ie, Cu (hfac) ₂ and (2L)) can be purged from a chamber that is typically maintained at a vacuum during wafer processing.

One problem with using Cupraselect for CVD can occur when delivering material from its liquid storage ampoule to the processing chamber where the CVD takes place.
Typically, the liquid Cupraselect is first vaporized and mixed with a carrier gas such as argon, helium, or other gas (usually an inert gas) between the ampoule and the processing chamber. A plurality of evaporators are incorporated within the delivery system, and typically the operation is accomplished by changing one of two environmental conditions (temperature or pressure). Many evaporators increase the temperature of the precursor to establish the desired state change. Unfortunately, too high a temperature can cause the precursors to decompose and subsequently cause plating (deposition) in the transfer line between the ampoule and the processing chamber. One example of a known evaporator is a GEM evaporator from Bronkhurst, the Netherlands, used to vaporize precursors. Unfortunately, these devices can be plugged with only about 50-1500 g of Cupraselect vaporized. These clogs can change the deposition rate. For many wafer manufacturing applications, it is preferred that the evaporation rate be reproducible from wafer to wafer.

  After vaporization, Cupraselect is frequently pumped into the processing chamber with an appropriate carrier gas. This pumping action draws a high concentration of TMVS from Cupraselect, leaving less stable copper and (hfac) in the transfer line between the ampoule, the delivery system, and the processing chamber. Under these conditions, undesired plating or deposition may occur at various locations. For example, plating can occur in the vicinity of evaporators, valves, orifices of showerheads in process chambers, and the like. Plating changes the size of these system components and can degrade the performance of the chamber and the resulting deposited layer. In addition, the plating can be undesirably stripped during the deposition process, rendering the wafer to be processed defective or unusable. Maintenance cycles performed on the processing chamber to replace or clean the processing chamber will reduce wafer throughput.

  In order to obtain a reproducible deposition condition, as disclosed in US patent application Ser. No. 09 / 120,004 (Docket No. 2460) dated 21 July 1998, there are various points within the delivery system. It is often desirable to generate precursor vapors as close as possible to the processing chamber to reduce the likelihood of deposition and to reduce the time and cost of purging the processing chamber. In the above patent application, the evaporator is located directly on the lid of the processing chamber, shortening the components used to deliver the precursor, reducing the chance of clogging, and when needed The system is easy to parse.

  In one aspect of the invention, an improved method and apparatus for vaporizing deposited material in a deposition process system is provided. For example, in the illustrated embodiment, the evaporator includes a body defining a cavity having an outlet and a recessed inlet, the cavity outlet being larger than the recessed cavity inlet. The evaporator body is further coupled to the inlet and further defines a first passage for carrying a mixed stream of carrier gas and liquid precursor to the cavity inlet. The passageway has a relatively short length and a small width so as to form small liquid precursor particles and inhibit the liquid precursor from recombining into large drops. The cavity is shaped such that it can expand as the mixed flow of carrier gas and liquid precursor flows from the cavity inlet to the cavity outlet. As a result, the liquid precursor is dispersed by the carrier gas and spreads throughout the cavity.

  In the illustrated embodiment, the evaporator is located on the lid of the chemical vapor deposition chamber. In another aspect, the evaporator further includes a hot plate disposed between the showerhead and the cavity outlet to vaporize the dispersed liquid precursor into a vaporized material. In the illustrated embodiment, a showerhead disposed within the chamber lid is adapted to dispense vaporized material and deposit it on a wafer or other workpiece.

  In one aspect of the illustrated embodiment, evaporator clogging can be reduced and deposition system throughput can be increased until purging or other cleaning is required.

  The above description is merely a summary of one embodiment of the present invention, and it should be understood that the embodiment disclosed below can be modified in many ways without departing from the spirit or scope of the present invention.

  For ease of understanding, the same reference numerals are given to the same elements throughout the drawings as much as possible.

1 is a schematic diagram of a CVD copper deposition system according to an embodiment of the present invention. It is sectional drawing of the evaporator and CVD chamber of FIG. It is an expanded sectional view of the evaporator of FIG. It is an expanded sectional view of the channel | path and cavity inlet_port | entrance of the evaporator of FIG. It is a 5-5 arrow top view of the hot plate of the evaporator of FIG. 1 is a schematic diagram of a control system for operating a deposition system. FIG.

  Features of the illustrated embodiment of the present invention include improved vaporization of precursor materials (eg, Cupraselect in the case of copper CVD) for delivery to the deposition system. In the following, the illustrated embodiment of the present invention will be described with reference to a thin film of copper grown by CVD, but those skilled in the art will be able to improve the resulting film and reduce the level of contamination in the system. It will be appreciated that it is applicable to any thin film deposition process where it is desirable to maintain a controlled and reproducible feed. Other liquid precursors or reactants include, but are not limited to, TEOS, trimethyl borate, tetraethyl borate, tetraethyl phosphate, tetraethyl phosphite, tetrakis (dimethylamino) titanium diethyl analog, and water. Copper compound precursors other than Cupraselect can also be used.

With particular reference to FIG. The chemical vapor deposition system 10 uses an evaporator 12.
The evaporator 12 vaporizes the reactant liquid in a manner that reduces the plugging of the evaporator. The liquid flow rate is controlled by a closed loop system between the liquid flow controller 14 and a system controller 17 that includes a programmed workstation. In the system 10, a liquid reactant 11 such as Cupraselect is supplied from a liquid bulk feed tank 16 to a heat or plasma enhanced CVD process chamber 18. The chamber 18 is conventional, except that the evaporator 12 is preferably directly attached to the lid 19 of the chamber 18, as will be described in detail below.
Examples of suitable chambers 18 (except for the lid modifications described above) are Adamik et al. US Pat. No. 5,000,113, Mar. 19, 1991, Foster et al. US Pat. No. 4,668,365, May 26, 1987, 1986. US Patent No. 4,579,080 issued April 1, Benz, et al., US Patent No. 4,496,609 issued January 29, 1985, and US Patent No. 4,232,063 issued November 4, 1980 by East et al.

  The liquid bulk supply tank 16 has a dip ring 20 extending into the tank 16 and a pressurized gas such as helium to drive the liquid out of the tank at the top of the tank 16 above the liquid reactant 11. A source 24 is included which feeds into the “head” space 26. The liquid flow controller 14 is connected between the liquid bulk supply tank 16 and the liquid inlet 30 of the evaporator 12. A controlled amount of liquid is supplied to the evaporator 12. The evaporator 12 converts the liquid into vapor and carries the vapor to the processing chamber 18 by a carrier gas such as helium, nitrogen, or argon. A gas tank 34 containing carrier gas is connected to the gas inlet 36 of the evaporator 12 through a mass flow controller 38 that regulates the gas flow rate. In many applications, the liquid 11 can be toxic and / or corrosive. To facilitate inspection of the system 10 and its component valves and other elements, a purge line is connected between the gas tank 34 and the liquid flow monitor so that the reactant liquid 11 is present before the operator checks the system 10. And its vapor can be purged from the system 10. To further reduce the amount of reactants in the system, a vacuum line 41 is used in conjunction with the purge line 39 to exhaust liquid and vapor from the system. (Vacuum lines 41 are coupled to the CVD system's vacuum system.) A remotely controllable (eg, pneumatic) valve 13 is inserted into each line. These valves open and close to allow normal operation and purge and exhaust operations. To increase safety and fault tolerance, each line with a remote control valve 13 can also have a manual valve 15 that can be manually closed if the remote control valve fails.

2-4 shows one embodiment of the evaporator 12 in detail. Reference is first made to FIG. The evaporator 12 includes a “nebulizer” stage 200 that mixes the liquid precursor 11 and the carrier gas. The carrier gas is adapted to expand rapidly. As a result, the liquid precursor is crushed and dispersed as small particles or droplets in the carrier gas and sent to the evaporator chamber 202 for vaporization. The term “atomizer” is not necessarily intended for the atomizer stage 200 to disperse the liquid precursor at the atomic level. However, the atomizer stage 200 disperses the liquid precursor into the aerosol dispersion in the carrier gas flow to the evaporator chamber 202. Aerosol particles can be, for example, in diameters ranging from 10 ⁻⁷ to 10 ⁻⁴ cm (4 × 10 ^{−8 to} 4 × 10 ⁻⁵ inches), and turbulent gas disperses particles 100 times larger Can do. In one application, an atomizer stage according to the illustrated embodiment has a size that is substantially less than 10 mils (0.010 inches) in size and closer to aerosol size particles in the carrier gas flow to the evaporator chamber 202. It is thought that the Cupraselect liquid precursor is dispersed like the liquid precursor particles of Of course, the size of the particles will vary depending on the application.

  The nebulizer stage 200 includes a valve body 204 that receives a liquid precursor flow through the liquid inlet 30 and a carrier gas flow through the gas inlet 36. The liquid inlet 30 includes a coupler 206 that receives one end of a liquid precursor supply line 208 from the liquid flow controller 14 (FIG. 1). The gas inlet 36 includes a coupler 210 that receives one end of a gas supply line 212 from the mass flow controller 38 via the control valve 13. The couplers 206 and 210 can be any known coupler design suitable for a particular application. Lines 208 and 212 may be flexible lines as disclosed in the above-mentioned co-pending application to facilitate opening and closing of the chamber lid 19.

  Reference is now made to FIGS. The valve body 204 of the nebulizer stage 200 includes a fluid passage 220. The fluid passage 220 is coupled to the liquid inlet coupler 206 by a second fluid passage 222 and is coupled to the gas inlet coupler 210 by a third fluid passage 224. As shown in FIG. 4, the valve body passage 220 receives the carrier gas flow 230 from the passage 224 (FIG. 3) and is arranged orthogonal to the first passage 220 in the illustrated embodiment. Liquid precursor stream 232 is received from passage 222 (FIG. 3). Such an arrangement results in a shearing T-cross 236. This causes the carrier gas stream 230 to “shear” the liquid precursor stream 232 at the intersections 236 (as represented by the portions 232a and 230a where the streams 232 and 230 are mixed). Promote mixing with.

  In the illustrated embodiment, the mixing passage 220 has a relatively narrow width as indicated by W in FIG. Reducing the width of the passage 220 is believed to facilitate the formation of relatively small particles or droplets when the liquid precursor stream 232 is sheared by the carrier gas stream 230 at the T intersection 236. In the illustrated embodiment, the mixing passage has a diameter in the range of 20-30 mils, but can be larger or smaller depending on the particular application.

  The mixing passage 220 has a pair of inlets 220a and 220b located at the T-intersection 236. One inlet 220 a is coupled to passage 222 and introduces liquid precursor from passage 222. The other inlet 220 b is coupled to the passage 224 and introduces carrier gas from the passage 224. In the illustrated embodiment, the mixing passage 220 has a relatively short total length from the liquid precursor inlet 220a to the cavity inlet 262, as indicated by L in FIG. When the length L of the mixing passage 220 is shortened relative to the width W of the mixing passage, the liquid precursor particles are dispersed when the mixed flow of carrier gas and liquid precursor flows from the T-intersection 236 to the cavity inlet 262. It is believed to prevent recombination into larger drops. In the illustrated embodiment, the ratio of the length L of the mixing passage 220 to its width W ranges from 2: 1 to 20: 1. This ratio can be varied depending on the application.

  The inlet 220 b of the mixing passage 220 is coupled to the reduced diameter portion 224 a of the carrier gas passage 224. In the illustrated embodiment, the reduced diameter portion 224 a has the same width as the mixing passage 220.

  The flow rate of the carrier gas from the larger diameter portion 224b of the gas passage 224 to the mixing passage 220 is accelerated by a narrowing nozzle portion 240 (FIG. 3) positioned in front of the narrowed gas passage 224a. . In the illustrated embodiment, the narrowing nozzle portion 240 is hemispherical and smoothly narrows the flow of gas into the reduced diameter passage 224a and the mixing passage 220. It is thought that when the gas flow is narrowed, the velocity of the gas flow is accelerated by the “Venturi effect”. In the illustrated embodiment, the nozzle portion 240 reduces the diameter of the gas passage 224 to approximately 1/10. The nozzle portion 240 in front of the mixing passage is optional and can have various other shapes including cylindrical and frustoconical.

Similarly, the flow rate of the liquid precursor from the liquid passage 222 to the mixing passage 220 is also accelerated by a narrowing nozzle positioned in the liquid passage 222 in front of the mixing passage 220. In the illustrated embodiment, the narrowing nozzle is realized by a “zero dead volume” valve, which is shown schematically at 244 in FIG. Other types of valves can also be used. The valve 244 includes a valve member, indicated generally at 246, which, when seated on the valve seat, closes the liquid passage 222 and blocks the flow of liquid precursor to the mixing passage 220. In the open position in which the valve member is displaced from the valve seat, the liquid flow through the valve is narrowed, similar to that of the gas flow, and the liquid precursor flow into the mixing passage is accelerated. The narrowing of the flow of liquid from the liquid passage 222 through the open valve 244 to the mixing passage 220 is illustrated schematically by the reduced diameter valve passage 244a in the passage 222. In the illustrated embodiment, the passage 244a has a diameter of approximately 10 mils, and the valve 244 effectively reduces the diameter of the liquid passage 222 to approximately 1/10. Details of the structure of the zero dead volume valve are known in the art and can take a variety of forms. However, when the valve is in the closed position, the volume of the closed passage (“dead leg”) of the valve 244 between the mixing passage 220 and the valve member 246 seated in the valve seat of the valve 244. It will be appreciated that the leg) (represented by the passage 244a) is preferably as small as possible and is therefore named "zero dead volume". By reducing the dead volume of the valve leg dead leg, the evaporator 12 can be easily cleaned and purged. In the illustrated embodiment, the volume of dead leg 244a purged when valve 244 is closed is less than 0.1 cc (cm ³ ), more preferably less than 0.001 cc.

  The dimensions of the valve can be varied depending on the application. Further, in some applications, the valve is optional.

  As shown in FIG. 3, the mixture of carrier gas and liquid precursor is delivered by a mixing passage 220 to a cavity 260 formed in the valve body 204. In the illustrated embodiment, the mixing passage 220 has a relatively constant diameter from the shear T 236 to the cavity 260 and the mixture is fed into the cavity 260 without substantial additional narrowing. It is like that. To reduce back pressure, it may be desirable to minimize the length of the reduced diameter passage in some applications. However, it is preferred that the mixing passage be sufficiently long so as to direct the mixed flow of carrier gas and liquid precursor to the center of the expansion cavity.

Cavity 260 includes a hemispherical inlet portion 260a followed by a generally cylindrical outlet portion 260b. The hemispherical inlet portion 260 a defines a cavity inlet 262 that is recessed into the cavity wall and fluidly connected to the end of the mixing passage 220.
In the illustrated embodiment, the cavity 260 is not provided with an injection tip or other inlet member that extends into the cavity. The opposite end of the cavity 260, ie, the cylindrical outlet portion 260 b, defines a cavity outlet 264 that has an inner diameter that is substantially greater than the inner diameter of the cavity inlet 262. As shown in FIG. 3, the cavity diameter increases monotonically from the hemispherical portion 260a. As a result, the mixture of carrier gas and liquid precursor exiting mixing passage 220 at cavity inlet 262 expands rapidly as it passes through hemispherical inlet portion 260a and is narrowed by hemispherical inlet portion 260a. Absent. This rapid expansion of the mixture stream is believed to promote the dispersion of the precursors, resulting in a very small aerosol flow carried by the rapidly expanding carrier gas stream.

  In the illustrated embodiment, the inner diameter of the cavity 260 remains substantially constant at the cylindrical outlet portion 260b. In the illustrated embodiment, the diameter of the outlet portion 260b is approximately 1/4 to 1/2 inch. The nebulizer stage cavity 260b may have a size and shape other than the hemispherical and cylindrical shapes shown and described. For example, depending on the application, a frustoconical cavity may be used. However, squeezing the cavities can increase the deposition of material on the walls of the cavities.

  As shown in FIG. 2, the evaporator chamber 202 of the evaporator 12 includes a housing 270 that defines a generally cylindrical evaporator chamber interior 272. An aerosol dispersion of liquid precursor and carrier gas is delivered by nebulizer outlet 264 to a central inlet 274 defined by housing 270 of evaporator chamber 202. The valve body 204 of the atomizer stage 200 is attached to the housing 270 of the evaporator chamber 202 such that the outlet of the atomizer 200 is aligned with the inlet 274 of the evaporator chamber 202. The connection between the nebulizer 200 and the evaporator chamber 202 is sealed using a suitable seal 276 (FIG. 3).

  In the illustrated embodiment, the evaporator chamber inlet 274 has a generally cylindrical portion 274a (FIG. 3) having the same inner diameter as the cylindrical portion 260b of the nebulizer cavity outlet 264, followed by a nozzle that extends in a frustoconical shape. Part 274b. Located within the chamber 272 and facing the evaporator chamber inlet 274 is a hot plate 280. The hot plate 280 is heated to a temperature sufficient to vaporize the liquid precursor particles carried to the hot plate 280 by the carrier gas.

  In the illustrated embodiment, the inner diameter of the evaporator chamber inlet 274 remains substantially constant at the cylindrical portion 274a and linearly and monotonically expands at the frustoconical portion 274b. The inlet 274 of the evaporator chamber 202 can have shapes other than the cylindrical and frustoconical shapes shown and described. For example, depending on the application, a hemispherical inlet can be used. However, narrowing at the inlet may increase material deposition on the inlet walls.

  As shown in FIG. 5, the hot plate 280 is disposed within the evaporator chamber interior 272 and has an annular outer zone 280a. Outer zone 280a defines a plurality of passages 282 disposed about outer zone 280a. Each hot plate passage 282 passes through the hot plate 280 to allow vaporized material to flow through the hot plate 280 and an opening 284 in the lid 19 of the processing chamber 18 into the interior 286 of the processing chamber 18. The size and number of passages 282 can vary depending on the application. In the illustrated embodiment, the passages are preferably of a sufficiently large size and sufficient number to reduce or eliminate a substantial drop in pressure as the steam passes through the hot plate.

The line of sight along the frustoconical portion 274b side indicated by the dashed line 290 (FIG. 2) intersects the central disk-shaped zone on the top surface of the hot plate 280.
As a result, the frustoconical portion 274b side of the evaporator chamber inlet 274 guides and vaporizes most of the dispersed liquid precursor material onto the central zone 280b of the hot plate 280. Depending on the application, other angles can be selected.

  As shown in FIGS. 2 and 5, the central zone 280b of the hot plate 280 has a plurality of concentric grooves 288 for receiving droplets of liquid precursor from the nebulizer stage 200 and evaporating them into vapor. These grooves increase the effective surface of the hot plate for transferring thermal energy to the droplets to vaporize the droplets. In addition, the grooves collect droplets that do not vaporize immediately until they receive sufficient energy to vaporize. The vaporized material passes through the hot plate passage 282 and the lid opening 284 to the interior of the deposition chamber 18, as indicated by the flow arrows 289.

  In the illustrated embodiment, the groove 288 of the hot plate 280 has a width in the range of 1/16 to 1/8 inch and a depth in the range of 1/4 to 1/2 inch. These dimensions can be varied depending on the application. The grooves are preferably sized so as to maintain good heat conduction without overcooling the top surface of the hot plate. In addition, the size of the grooves can affect manufacturing costs and cleaning efficiency.

  The evaporator 12, including the valve body 204, chamber housing 270, and hot plate 280, is heated by a heating jacket 292 that surrounds the outside of the evaporator chamber housing 270 and the outside of the hot plate outer zone 280a. . In the illustrated embodiment, the components of the evaporator 12 including the valve body 204, the evaporator chamber housing 270, and the hot plate 280 are made of aluminum. It should be understood that other materials can be used, including other high thermal conductivity materials. In the illustrated embodiment, the temperature of the components of the evaporator chamber including the nebulizer stage 200 and the hot plate 280 that may come into contact with the liquid precursor or vapor is controlled. These temperatures are preferably high enough to promote vaporization of the liquid precursor, but preferably low enough to avoid chemical degradation. In the illustrated embodiment where the liquid precursor is Cupraselect, the temperature range of these components is preferably 70-75 ° C. Of course, this temperature range can be varied depending on the application. Alternatives to the heating jacket include, but are not limited to, fluid exchange with remotely heated fluid, hot plate 280, resistance heating elements included in / on the chamber housing 270 or valve body 204, and in the chamber Heating can be accomplished by any known and accepted means for heating the chamber components, such as a heating lamp (not shown). If the hot plate is heated by applying heat to or into the hot plate outer zone 280a, the hot plates are adjacent so that sufficient heat can be transferred to the hot plate inner zone 280b. It is preferable to leave enough material in the outer zone 280a between the passages 282.

  The evaporator chamber housing 270 is mounted on the hot plate outer zone 280b and the outer zone 280b itself is mounted on the lid 19 in alignment with the opening 284 in the deposition chamber lid 19. The connection between the evaporator hot plate 280 and the deposition chamber lid 19 is sealed by a suitable seal 300 (FIG. 2), such as the connection between the evaporator housing 270 and the hot plate 280. Deposition chamber 18 is limited by side walls 302, floor 304, and lid 19. The lid 19 incorporates a shower head 308 having a plurality of orifices 310 for distributing vapor to be deposited. The deposition chamber 18 further includes a heated substrate support 312 for holding a substrate 316 such as a semiconductor wafer where it is desired to deposit copper. The substrate support 312 is made of a durable metal material such as aluminum, or a ceramic such as aluminum nitride or boron nitride. The substrate support 312 also functions as a heater or heat sink and includes additional components for heating the wafer 316 or extracting heat from the wafer 316. For example, the substrate support 312 can be provided with one or more resistance heater coils 313 connected to a power source. The flow of current supplied from the power source to the coil 313 generates heat in the substrate support 312 and this heat is transferred to the wafer 316. An annular plate 314 is attached to the chamber wall 302 and provides a support for the cover ring 318. When the vaporized precursor from the evaporator 12 contacts the heated wafer, copper is deposited on the substrate 316 by CVD. A cover ring 318 protects the peripheral portion of the substrate 316 where deposition is not desired and the lower chamber region. A pressure control unit 342 (eg, a vacuum pump) is coupled to the processing chamber 18 via a valve 338 (eg, a throttle valve) to control the chamber pressure.

  The showerhead in the deposition chamber is optional and can be any known showerhead. Further, the showerhead can be configured as described in the above-mentioned cending application. As described in the application, the showerhead 308 is not only as a distribution plate for vaporized precursor and carrier material, but also a secondary “hot plate” for capturing and revaporizing excess processing material. It ’s also useful. The showerhead 308 performs this function with a plurality of concave segments 326 optionally formed on the top surface of the showerhead 308 and optionally a shadow plate 324 disposed on the showerhead 308. A fully vaporized process material stream flows from the evaporator 12 into the chamber 18. The flow 343 continues to pass through the plurality of orifices 344 provided in the shadow plate 324 and the plurality of orifices 310 in the showerhead 308. The shadow plate orifice 344 is offset from the showerhead orifice 310 to reduce contamination by the liquid precursor. That is, the incompletely vaporized (liquid) material stream 345 from the evaporator 12 is captured by one of the concave portions 326 on the top of the showerhead 308. Shower head 308 and shadow plate 324 are heated to approximately 65 ° C., a temperature suitable for vaporizing the liquid precursor material (ie, Cupraselect). This heating may include, but is not limited to, fluid exchange with remotely heated fluid, resistance heating elements included in / on the showerhead 308 and / or shadow plate 324, and heating lamps in the chamber, etc. This is accomplished by any known and accepted means for heating the chamber components. This vaporizes the liquid material and follows a passage 347 through one of the plurality of orifices 310 in the showerhead 308. Incomplete vaporized material flow may also occur along the passage 350, but will begin to vaporize on the shadow plate 324 and continue to flow along the passage 352 as a vaporized flow. The shower head 308 and the shadow plate 324 are thought to prevent the flow of liquid material to the wafer surface by capturing and secondary vaporizing such liquid.

  Each of the various components described above, such as hot plate 280, housing 270, or valve body 200, can each be manufactured as a unitary or single piece structure. Alternatively, depending on the particular application, these components can be assembled from subcomponents.

  The apparatus and processes described above can be performed in a system controlled by a processor-based control system 17 (FIG. 1). FIG. 6 is a block diagram of a deposition system 10 as shown in FIG. 1 and has a control system 17 that can be used for such capabilities. The control system 17 includes a processor unit 802, a memory 804, a mass storage device 806, an input control unit 808, and a display unit 810, all coupled to a control system bus 812.

  The processor unit 802 forms a general-purpose computer. However, the processor unit 802 becomes a dedicated computer when executing a program such as the program for performing copper CVD in the illustrated embodiment. Although this embodiment is described as being implemented in software and executed on a general purpose computer herein, the present invention is not limited to an application specific integrated circuit ASIC or other hardware, provided that the person skilled in the art is familiar. It will be understood that it can be operated using hardware such as a wear circuit. Therefore, it should be understood that all or part of the control surface of the embodiment of the present invention can be realized by software, hardware, or both.

The processor unit 802 is either a microprocessor or other engine that can execute instructions stored in memory. Memory 804 may comprise a hard disk drive, random access memory (“RAM”), read only memory (“ROM”), a combination of RAM and ROM, or another processor readable storage medium. Memory 804 contains instructions that processor unit 802 executes to perform operations of deposition system 10.
The instructions in the memory 804 are in the form of program code. The program code follows any one of many different programming languages. For example, the program code can be written in C +, C ++, basic, Pascal, or many other languages.

  The mass storage device 806 stores data and instructions and retrieves data and program code instructions from a processor readable storage medium such as a magnetic disk or magnetic tape. For example, the mass storage device 806 can be a hard disk drive, a floppy disk drive, a tape drive, or an optical disk drive. The mass storage device 806 stores and retrieves instructions in response to instructions it receives from the processor unit 802. Data and program code instructions stored and retrieved by the mass storage device 806 are used by the processor unit 802 to operate the deposition system 10. Data and program code instructions are first retrieved from the medium by mass storage device 806 and then transferred to memory 804 for use by processor unit 802.

  The display unit 810 provides information to the chamber operator in the form of a graphic display and alphanumeric characters under the control of the processor unit 802. The input control unit 808 couples a data input device such as a keyboard, mouse, or light pen to the processor unit 802 for receiving chamber operator input.

  Control system bus 812 transfers data and control signals between all devices coupled to control system bus 812. Although the control system bus is shown as a single bus that directly connects the devices in the processor unit 802, the control system bus 812 can also be a collection of buses. For example, display unit 810, input control unit 808, and mass storage device 806 can be coupled to an input / output peripheral bus, while processor unit 802 and memory 804 can be coupled to a local processor bus. The local processor bus and the input / output peripheral bus are coupled together to form a control system bus 812.

  The control system 17 is coupled to the elements of the deposition system 10 used in copper CVD according to the illustrated embodiment. Each of these elements is coupled to a control system bus 812 and communicates between the control system 17 and the elements. These elements include a plurality of valves 814 (such as valves 13 and 15 in FIG. 1), a heating element (such as heating element 113 and heating jacket 292 in FIG. 2), a pressure control unit 342, a flow controller (see FIG. 1, such as flow controller 14 and 38), evaporator 12 (including valve 244 in FIG. 3), and pressure source controller (such as pressure source 24 in FIG. 1). The control system 17 provides signals to the chamber elements and causes them to perform operations to form a copper layer within the associated apparatus.

  The operation will be described. The processor unit 802 commands the operation of the chamber elements in response to program code instructions received from the memory 804. For example, when a wafer is placed in the processing chamber, the processor unit 802 may retrieve instructions from the memory 804 (eg, a valve 814 to generate a desired flow rate of precursor and carrier material that energizes the heating element 313. And the substrate support 312 is moved to a position for CVD. Execution of these instructions activates elements of the deposition system 10 to deposit a layer of material on the substrate.

  The novel deposition system described above can provide improved CVD operation by distributing the vaporized precursor material more completely and more uniformly within the chamber. In addition, various features of the present deposition system can cause undesirable clogging or overloading and plating that potentially creates particles in the chamber and / or results in premature failure or over-maintenance of system components. Including reducing the possibility.

  The foregoing description is merely illustrative of some embodiments of the present invention, and that many modifications can be devised in accordance with the above disclosure without departing from the spirit or scope of the present invention. I want you to understand. Accordingly, the above description is not intended to limit the scope of the invention, which is limited only by the scope of the claims.

DESCRIPTION OF SYMBOLS 10 CVD copper deposition system 11 Liquid reactant 12 Evaporator 13 Remote control valve 14 Liquid flow controller 15 Manual valve 16 Liquid bulk supply tank 17 System controller 18 CVD process chamber 19 Chamber lid 20 Dip tube 24 Pressurized gas source 26 Head space 30 Liquid inlet 34 Gas tank 36 Gas inlet 38 Mass flow controller 41 Vacuum line 200 Nebulizer 202 Evaporator chamber 204 Valve body 206, 210 Coupler 208 Liquid precursor supply line 212 Gas supply line 220, 222, 224 Fluid passage 230 Carrier gas Flow 232 Fluid precursor flow 236 Shear T crossing 240 Narrowing nozzle portion 244 Zero dead volume valve 246 Valve member 260 Cavity 262 Cavity inlet 264 Cavity out Mouth 270 housing 272 evaporator chamber interior 274 central inlet 276 seal 280 hot plate 282 passage 284 process chamber opening 286 process chamber interior 288 groove 289 vaporized material flow 292 heating jacket 300 seal 302 side wall 304 floor 308 showerhead 310 orifice 312 susceptor 313 heater coil 314 annular plate 316 wafer 318 cover ring 324 shadow plate 326 concave segment 338 throttle valve 342 pressure control unit (vacuum pump)
343 Process material flow 344 Orifice 345, 350 Incompletely vaporized material flow 347, 352 Re-vaporized material flow 802 Processor unit 804 Memory 806 Mass storage device 808 Input control unit 810 Display unit 812 Control system bus 813 Heating element 814 valve

Claims (17)

An evaporator for use with a carrier gas source, a liquid precursor source, and a deposition chamber for performing chemical vapor deposition,
A valve body defining a cavity having an outlet and an inlet, the valve body being further coupled to the cavity inlet and further having a first passage for carrying a flow of carrier gas and liquid precursor to the cavity inlet. And the first passage has a liquid precursor inlet and defines a width W and a length L between the liquid precursor inlet and the cavity inlet, and the valve body includes the first A second passage coupled to the liquid precursor inlet of the passage and for transporting a liquid precursor flow to the first passage; and a carrier gas flow coupled to the first passage for the first passage. And a third passage for directing the carrier to direct the flow of carrier gas through the liquid precursor inlet, wherein the carrier gas flow shears the liquid precursor flow. Then liquid A precursor is formed into a droplet, and the liquid precursor droplet and the carrier gas are mixed to form a flow formed between the liquid precursor inlet and the cavity inlet. The ratio of the length L to the width W of the first passage between the material inlet and the cavity inlet does not exceed 20: 1, and the cavity is expanded by the carrier gas by the cavity. The liquid precursor droplets can be dispersed, and the evaporator further includes a hot plate that faces the cavity outlet and vaporizes the dispersed liquid precursor into vaporized material. In addition,
An evaporator characterized by that.   The evaporator according to claim 1, wherein the ratio of the length L to the width W of the first passage is at least 2: 1.   The evaporator of claim 1, wherein the length of the first passage is less than 100 mils, where 1 mil = 1/1000 inch and 1 inch is about 2.54 cm. .   The evaporator of claim 1, wherein the first passage is less than 30 mils, where 1 mil = 1/1000 inch, where 1 inch is about 2.54 cm.   The evaporator according to claim 1, wherein the cavity entrance is recessed.   The valve body further includes a valve disposed in the second passage, the valve having an open position and a closed position, and when in the open position, from the second passage. The evaporator according to claim 1, wherein the flow of the liquid precursor is allowed to pass through the first passage.   The evaporator according to claim 6, wherein the valve is a zero dead volume valve.   The second passage defines a dead leg portion between the valve and the first passage when the valve is in the closed position, and the dead leg portion has a volume of 0.1 cc or less. The evaporator according to claim 6, wherein the evaporator is provided.   The evaporator according to claim 8, wherein the dead leg portion has a volume of 0.001 cc or less.   The flow of carrier gas from the third passage through the first passage mixes the flow of liquid precursor from the second passage with the carrier gas flowing through the first passage; The evaporator of claim 1, wherein the second passage is coupled to the first passage.   2. The first passage has a first flow cross-sectional area, and the second passage has a second flow cross-sectional area that is smaller than the first flow cross-sectional area. The evaporator as described in.   2. The first passage has a first flow cross-sectional area, and the third passage has a third flow cross-sectional area that is larger than the first flow cross-sectional area. The evaporator as described in.   The evaporator according to claim 1, wherein the cavity has a flow cross-sectional area that monotonically increases from the cavity inlet to the cavity outlet.   The evaporator according to claim 1, wherein the hot plate has a surface facing the cavity outlet and defining a plurality of grooves.   The evaporator according to claim 14, wherein the grooves of the hot plate are concentric.   15. The evaporation of claim 14, wherein the groove of the hot plate has a width in the range of 1/16 to 1/8 inch, wherein 1 inch is about 2.54 cm. vessel.   The groove of the hot plate has a depth in the range of 1/4 to 1/2 inch, wherein 1 inch is about 2.54 cm. Evaporator.

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